Preparing for Climate Change: Forestry and Assisted Migration

Mary I. Williams and R. Kasten Dumroese

Although plants have moved across the landscape in response to changing climate for millennia, projections of and patterns of genetic variation within and contemporary climate change suggest that forest tree species and populations will need to migrate faster than among populations (Campbell 1974, 1979, their natural ability. Therefore, climate change adaptation strategies, such as assisted migration, have gained Morgenstern 1996). Growing season length attention since 2007. Effective implementation of assisted migration can only occur if target transfer guidelines (i.e., frost-free season) has increased and will are developed because our current seed transfer guidelines, established to guide the movement of plant continue to lengthen under contemporary materials, lack inherent spatial and temporal dynamics associated with climate change. This limitation restrains climate change (US Environmental Protec- reforestation practitioners from making decisions about assisted migration. Lack of operating procedures, tion Agency 2010, Walsh et al. 2013). Al- uncertainties about future climate conditions, risks associated with moving plants outside their current ranges, though a longer growing season may cause and existing policies have hampered formal actions in forest management and conservation. We review the an increase in forest productivity, it will current thinking on assisted migration of forest tree species and provide information that could facilitate probably be offset by increased evaporation, implementation. transpiration, and soil drying, thus making forest systems vulnerable to earlier and lon- Keywords: assisted migration, climate change, forest management, seed transfer, seed zones ger ﬁre seasons (Trenberth 2011, Joyce et al. 2013, Walsh et al. 2013). Furthermore, because initiation and cessation of growth are limate has played a major role in 2008). Long-lived species, such as trees, will inﬂuenced by temperature, precipitation, shaping vegetative growth, compo- lag behind short-lived species in their ability sition, and genetic variation across to adapt and track suitable climate condi- and light (Morgenstern 1996), forest sys- C tems are likely to experience phenological landscapes (Jansen et al. 2007). Contempo- tions (Jump and Penuelas 2005, Lenoir et al. rary changes in our atmosphere have caused 2008, Vitt et al. 2010). It may take several imbalances with longer growing seasons global mean temperatures to increase at rates generations (centuries to millennia) for a such that bud break may occur earlier in the not previously experienced in geologic time tree population to become adapted through spring, making those individual trees sus- (Intergovernmental Panel on Climate evolution to a new climate (Beaulieu and ceptible to weather events (e.g., freezing Change [IPCC] 2007) such that climate ap- Rainville 2005, Ledig et al. 2012). temperatures and snowfall) and pest damage pears to be changing faster than plants can The mismatch in rates between climate (Parmesan 2007, Groffman et al. 2013, adapt or migrate (Zhu et al. 2012, Gray and change and tree adaptation will have serious Joyce et al. 2013). The expected impacts on Hamann 2013). Current climate projec- impacts on forest growth and composition forests are not unlike what we have already tions require plants, in general, to annually and, subsequently, important consequences observed, such as landscape-scale tree mor- migrate 9,842Ϫ16,404 ft (3,000Ϫ5,000 for management and conservation (McKen- tality due to mountain pine beetle outbreaks m), which far exceeds their observed rates of ney et al. 2009, Chmura et al. 2011, Lo et al. in the Rocky Mountains (Bentz et al. 2010) less than 1,640 ft (500 m) (Davis and Shaw 2011). Synchronization of tree growth with and prolonged drought and high tempera- 2001, Aitken et al. 2008, Lempriere et al. seasonal cycles plays a major role in adaption tures in the southwestern United States

Received February 18, 2013; accepted May 31, 2013; published online July 4, 2013. Afﬁliations: Mary I. Williams ([email protected]), Michigan Technological University, School of Forest Resources and Environmental Science, USDA Forest Service, Rocky Mountain Research Station, Moscow, ID. R. Kasten Dumroese ([email protected]), USDA Forest Service, Rocky Mountain Research Station. Acknowledgments: This collaborative work between Michigan Technological University, School of Forest Resources and Environmental Science and the USDA Forest Service, Rocky Mountain Research Station, Grassland, Shrubland, and Desert Ecosystems Program is accomplished through Joint Venture Agreement 11-JV- 11221632-130, partially funded by the National Center for Reforestation, Nurseries, and Genetics Resources. We thank Dr. Martin Jurgensen for his contributions to this work . We also thank Randy Johnson, Bryce Richardson, Jerry Rehfeldt, and three anonymous individuals for reviewing this manuscript.

Journal of Forestry • July 2013 287 (Breshears et al. 2005) and Canadian boreal uals in a geographic region having similar (Rehfeldt 1983, Campbell 1986, Lindgren forests (Michaelian et al. 2011). The im- genetic traits and climate adaptive ability) of and Ying 2000). pacts will intensify during the latter half of commercial trees could be moved within The intentional movement of species in this century with forest systems continuing their current range (i.e., assisted population response to climate change does not come to experience shifts in phenology (Chuine migration) or from their current range to without ethical, economical, legal, political, 2010) and range (Zhu et al. 2012, Gray and suitable areas just outside to keep pace with and ecological issues (Schwartz et al. 2012). Hamann 2013) and plants becoming poorly changing climatic conditions (i.e., assisted Assisted migration is a sensitive strategy be- adapted to the local climate where they are range expansion; Figure 1A and B). Move- cause it disrupts conservation objectives and growing (Aitken et al. 2008). For example, ment to locations far outside a species’ cur- paradigms and raises scientific, policy, and suitable climate conditions for western larch rent range is an option to prevent species ethical questions (McLachlan et al. 2007). (Larix occidentalis) will shift northward and extinction (i.e., assisted species migration; Adoption requires us to balance extinction upward in elevation during the next 90 years Figure 1C). For example, the rare tree Flor- or preservation of species against risks posed at a rate that exceeds its natural migration ida torreya (Torreya taxifolia) has been by introduced species (e.g., invasion) (Rehfeldt and Jaquish 2010). Without hu- planted on private lands in five US states (Schwartz 1994). The debate, discussed man assistance, some plant species will be outside its current and historic range in an thoroughly elsewhere, is largely focused on unable to adapt or migrate fast enough to effort to curtail extinction (Torreya Guard- the assessment of risks and benefits (e.g., track projected changes in climate. ians 2012). Ricciardi and Simberloff 2009, Aubin et al. During the past 30 years, climate Economic costs and ecological risks 2011, Hewitt et al. 2011, Lawler and Olden change adaptation strategies have been pro- (e.g., establishment failure or invasion) can 2011). Uncertainty about future climate posed. One strategy is assisted migration vary widely across the forms and goals of conditions and risks, such as genetic pollu- (Peters and Darling 1985), defined as the assisted migration (Figure 1) but will prob- tion, hybridization, impairment of ecologi- movement of species and populations to fa- ably increase with migration distance (Mu- cal function and structure, introduction of cilitate natural range expansion in direct eller and Hellmann 2008, Vitt et al. 2010, pathogens, and bringing on invasive species management response to climate change Pedlar et al. 2012). Moving the species or are major constraints to consensus and im- (Vitt et al. 2010). Drawing from conven- population before the recipient site is suit- plementation (Gunn et al. 2009, Aubin et al. tional reforestation practices and proposed able and inappropriate matching of the seed 2011). adaptation strategies, we review the current source with the outplanting site in a pro- thinking on assisted migration of forest tree jected area could increase establishment fail- Forestry and Assisted Migration species and provide information for nursery ure (Vitt et al. 2010). Assisted migration to In the literature discussing assisted mi- managers, land managers, and restoration- areas far outside the current range of a spe- gration of plants, forest tree species are high- ists to consider in management planning. cies (e.g., Florida torreya) would carry lighted most often because of their eco- Unlike recent reviews covering assisted mi- greater financial responsibilities and ecolog- nomic value and focus in climate change gration, we expand implementation and ical risks than assisted population migration research; however, assisted migration con- provide options, resources, and tools to and assisted range expansion (Winder et al. ducted for economic rather than conserva- move forward. Our primary focus is on for- 2011). Principle to in reforestation success is tion reasons is also cited as a major barrier to est tree species and populations, but the in- using locally adapted plant materials; thus, implementation (Hewitt et al. 2011), mean- formation we provide is relevant to other na- the greater the difference between seed ori- ing that economic benefit may be an insuf- tive plant species. gin and outplanting site, the greater the risk ficient justification. We must recall, though, in maladaptation. In other words, an in- that the need for good timber resources An Adaptive Strategy crease in distance (either geographic or cli- played a significant role in the advancement The climate will change more rapidly matic) is usually associated with loss in pro- of natural sciences, such as genecology (the than some populations can adapt, and many ductivity, decrease in fitness, or mortality study of genetic variation in relation to the landscapes are so fragmented that natural migration is limited (Crowe and Parker 2008, Hannah 2008). Humans have been moving plants for millennia, but the inten- Management and Policy Implications tional movement as an adaptive strategy to Climate is changing at a faster pace than natural plant migration, which poses a major challenge to forest climate change has only recently attracted management and conservation. We can draw from a century of forest research and management to curtail attention (Aubin et al. 2011, Hewitt et al. 2011, Ste-Marie et al. 2011). Assisted mi- losses in forest growth, productivity, and conservation by implementing strategies, such as assisted gration can fulfill diverse goals, such as pre- migration. Even though we have seed transfer guidelines and seed zones for many commercial tree venting species extinction, minimizing eco- species, we lack clear, standard operating procedures to determine how, when, and where to implement nomic loss, and sustaining ecosystem movement. Movements outside current guidelines and zones may run afoul of legal restrictions and state services and biodiversity (Figure 1) (Aubin and federal directives, but facilitating climatic adaptation through assisted migration has the potential to et al. 2011, Ste-Marie et al. 2011, Winder et preserve forest health and productivity, subsequently maintaining ecosystem services, such as carbon al. 2011, Schwartz et al. 2012). For example, sequestration, soil and water conservation, timber, and wildlife habitat. Our review and presentation of to avoid economic loss (e.g., wood volume) current information for researchers, foresters, landowners, and nurseries provides components to consider in the timber industry, seed sources and in their climate change adaptation plans. populations (group of intermating individ-

288 Journal of Forestry • July 2013 2001). Similarly, Douglas-fir (Pseudotsuga menziesii) has been planted around the Pa- cific Northwest to evaluate their growth response to climatic variation (Erickson et al. 2012). In Canada, several provinces have mod- ified policies or developed tools to enable assisted migration. Seed transfer guidelines for Alberta were revised to extend current guidelines northward by 2° latitude and upslope by 656 ft (200 m) (Natural Resources Canada 2013) and guidelines for some species were revised upslope by 656 ft (200 m) in British Columbia (O’Neill et al. 2008). Alberta is considering ponderosa pine (Pinus ponderosa) and Douglas-fir, now absent in the province, as replacements for lodgepole pine (Pinus contorta) because it is predicted to decline in productivity or suffer from extinction under climate change (Pedlar et al. 2011). Policy in British Columbia also al- lows the movement of western larch to suitable climatic locations just outside its current range (Natural Resources Canada 2013). To test species range limits in Que- bec, northern sites are being planted with a mixture of seed sources from the southern Figure 1. Assisted migration can occur in a variety of forms to fulfill diverse goals (Ste-Marie portion of the province. Using seed transfer et al. 2011, Winder et al. 2011). To avoid economic loss in the timber industry, seed sources and provenance data of several commercial and populations (e.g., genotypes) of commercial trees could be moved within their current tree species, Quebec and Ontario have tools range (A) or from their current range to suitable areas just outside (B) to keep pace with available that guide seed transfer decisions changing conditions (e.g., warmer climates). Movement to locations far outside current within their provinces (e.g., Optisource ranges is an option to prevent species extinction (C). Risks can vary widely across the forms [Beaulieu 2009] and BioSim [Regniere and of assisted migration but would probably increase with migration distance (Mueller and Saint-Amant 2008] in Quebec and Seed- Hellmann 2008, Vitt et al. 2010, Pedlar et al. 2012). For example, assisted migration to Where in Ontario [McKenney et al. 1999]). areas far outside its current range (e.g., C) would carry greater financial responsibilities and ecological risks (Winder et al. 2011). The lack of assisted migration projects in the United States does not suggest that natural resource agencies, managers, land environment) (Langlet 1971). Given its of long-term experiments undertaken by the owners, and stakeholders are not consider- long tradition of research, development, and British Columbia Ministry of Forests and ing it as a climate change strategy; for exam- application of moving genetic resources several collaborators, including the US De- ples, see Anderson and Chmura (2009), Er- through silvicultural operations, the forestry partment of Agriculture (USDA) Forest Ser- ickson et al. (2012), Finch (2012), Gunn et profession is well suited to evaluate, test, and vice and timber companies, that tests as- al. (2009), and St. Clair and Howe (2009). use an assisted migration strategy (Beaulieu sisted migration and climate warming The USDA Forest Service anticipates using and Rainville 2005, Anderson and Chmura (Marris 2009). The program evaluates the assisted migration of species to suitable hab- 2009, McKenney et al. 2009, Winder et al. adaptive performance of 16 tree species col- itats to facilitate adaptation to climate 2011). For commercial forestry, assisted mi- lected from a range of sources in British Co- change (USDA Forest Service 2008). How- gration can address the maintenance of pro- lumbia, Washington, Oregon, and Idaho ever, these management statements imply ductivity and health in the coming decades and planted on a variety of sites in British that assisted migration should only be im- (Gray et al. 2011) and would pose fewer eco- Columbia. Important components of the plemented in cases in which past research logical risks and economic costs because op- trial test how sources planted in northern supports success (Johnson et al. 2013). Un- erational frameworks already exist and re- latitudes perform as the climate changes and certainties about future climate conditions, quire only slight modifications (Pedlar et al. evaluate endurance of northern latitude risks associated with moving species and 2012). sources to warmer conditions in southern populations outside their current ranges, Forest management policy drafts to en- latitudes. In the United States, movement and existing policies have hampered prelim- courage assisted migration and trials of as- has been practiced for decades in the south- inary studies and formal actions. Across fed- sisted migration are currently underway in east with southern pines (Pinus spp.), for eral, state, and private groups in the United North America. The Assisted Migration Ad- which seed sources are moved one seed zone States, very few adaptation and mitigation aptation Trial (AMAT) is a large collective north to increase growth (Schmidtling plans have been implemented or evaluated

Journal of Forestry • July 2013 289 Table 1. Resources related to native plant transfer guidelines, climate change, and assisted migration for the United States and Canada.

Resource or program Description Authorship

Center for Forest Provenance Data Public users able to submit and retrieve tree Oregon State University and USDA Forest Service cenforgen.forestry.oregonstate.edu/index.php provenance and genecological data Centre for Forest Conservation Genetics Portal for forest genetics and climate The University of British Columbia www.genetics.forestry.ubc.ca/cfcg/ change research conducted in British Columbia, Canada Climate Change Resource Center Information and tools about climate change USDA Forest Service www.fs.fed.us/ccrc/ for land managers and decisionmakers Climate Change Tree Atlas An interactive database that maps current USDA Forest Service www.nrs.fs.fed.us/atlas/tree/tree_atlas.html (2000) and potential status (2100) of eastern US tree species under different climate change scenarios Forest Seedling Network Interactive website connecting forest Forest Seedling Network www.forestseedlingnetwork.com landowners with seedling providers and forest management services and contractors; includes seed zone maps Forest Tree Genetic Risk Assessment System (ForGRAS) Tool to identify tree species at risk of North Carolina State University and USDA Forest www.forestthreats.org/research/projects/project- genetic degradation in the Pacific Service summaries/genetic-risk-assessment-system Northwest and Southeast MaxEnt (Maximum Entropy) Software that uses species occurrences and Phillips et al. (2006) www.cs.princeton.edu/ϳschapire/maxent/ environmental and climate data to map potential habitat; can be used to develop seed collection areas Native Seed Network Interactive database of native plant and Institute for Applied Ecology www.nativeseednetwork.org/ seed information and guidelines for restoration, native plant propagation, and native seed procurement by ecoregion Seed Zone Mapper An interactive seed zone map of western USDA Forest Service www.fs.fed.us/wwetac/threat_map/SeedZones_Intro.html North America; user selects areas to identify provisional and empirical seed zones for grasses, forbs, shrubs, and conifers; map displays political and agency boundaries, topography, relief, streets, threats, and resource layers Seedlot Selection Tool An interactive mapping tool to help forest Oregon State University and USDA Forest Service sst.forestry.oregonstate.edu/index.html managers match seedlots with outplanting sites based on current climate or future climate change scenarios; maps current or future climates defined by temperature and precipitation SeedWhere GIS tool to assist nursery stock and seed Natural Resources Canada, Canadian Forest glfc.cfsnet.nfis.org/mapserver/seedwhere/seedwhere- transfer decisions for forest restoration Service about.php?langϭe projects in Canada and the Great Lakes region; can identify geographic similarities between seed sources and outplanting sites System for Assessing Species Vulnerability (SAVS) Software that identifies the relative USDA Forest Service www.fs.fed.us/rm/grassland-shrubland-desert/ vulnerability or resilience of vertebrate products/species-vulnerability/ species to climate change; provides a framework for integrating new information into climate change assessments

Most programs are easily located by searching their names in common web browsers. All URLs were valid as of June 21, 2013. despite the increase in the amount of land gration (Table 1). Bioclimatic models cou- dication of how climatic conditions will management planning during the past 30 pled with species genetic information in a change for a particular site. As foresters, we years (Bierbaum et al. 2013). Frameworks geographic information system (GIS) can be can gain considerable knowledge from past (e.g., Hoegh-Guldberg et al. 2008, Richard- used to identify current and projected distri- reintroductions, given our long history of son et al. 2009, Vitt et al. 2010, McDonald- butions (e.g., Rehfeldt and Jaquish 2010, moving and reestablishing species and from Madden et al. 2011), tools (e.g., McKenney McLane and Aitken 2012, Notaro et al. provenance trials established across a wide et al. 1999, Howe et al. 2009, Lawler and 2012). Although modeled projections have range of latitudes (Maschinski and Haskins Olden 2011), and implementations (e.g., some uncertainty (i.e., in future climate pre- 2012, Pedlar et al. 2012). Provenance stud- Pedlar et al. 2011) have been introduced to dictions and tree responses, as discussed in ies, originating in France in 1745 (Langlet make informed decisions about assisted mi- Park and Talbot 2012), they provide an in- 1971), evaluate the performance and growth

290 Journal of Forestry • July 2013 of populations from different geographic locations grown in common garden sites (Jump et al. 2009, Erickson et al. 2012). In the following sections, we consult the current literature and address implementation of assisted migration. Albeit similar to conventional reforestation approaches that foresters have been practicing for more than a century, assisted migration will be funda- mentally dictated by space, time, and, of course, available plant materials. In lieu of detailing specific, conventional instructions, we illustrate implementation from an assisted migration and climate change per- spective and highlight some of the spatial and temporal challenges. The Nursery Man- ual for Native Plants (Dumroese et al. 2009), Raising Native Plants in Nurseries: Basic Con- cepts (Dumroese et al. 2012), volumes of The Container Tree Nursery Manual (Landis et al. 1989, 1998, 2010), The Society for Ecolog- ical Restoration International Primer on Eco- logical Restoration (Society for Ecological Restoration 2004), and the Woody Plant Seed Manual (Bonner et al. 2008) are some resources to consult for seed and plant collection, propagation, site selection and preparation, outplanting, and maintenance. Spe- cifically, the Target Plant Concept (Landis et al. 2010), which is the culturing of stock types for specific outplanting goals and objectives, has been practiced in reforestation operations during the past 30 years and can be applied to assisted migration plans. Figure 2. A decision framework from Hoegh-Guldberg et al. (2008) to determine adaption strategies for a plant species or population that has conservation, economic, or social value. Implementation Genetic information, bioclimatic models, historical records, and current assisted migration experiments can be consulted in navigating the framework (see Lawler and Olden 2011). Species Selection Implementation of assisted migration is dependent on the species’ risk of decline or Of the published frameworks, a deci- extinction, establishment, and biological, economic, and social benefits and costs. sion matrix presented by Hoegh-Guldberg et al. (2008) helps to identify species risk and genetic degradation in the Pacific Northwest tion plans would be sufficient for species at feasibility of migration under climate and Southeast using the Forest Tree Genetic low risk, whereas species at moderate or high change (Figure 2). Species most vulnerable Risk Assessment System (ForGRAS). Prov- risk require more involved actions. Assisted to climate change are rare, long-lived, locally enance and distribution data exist for several migration might be warranted if a species is adapted, geographically and genetically iso- commercial tree species and can be used to at high risk of decline or extinction and can lated, and threatened by fragmentation and estimate their response to climate scenarios be established, and its migration provides insect and disease outbreaks (Erickson et al. (e.g., Leites et al. 2012). The Center for For- more benefit than cost. Conservation and 2012). Assisted migration can target com- est Provenance Data provides an online da- facilitating adaptation are alternative op- mercial tree species that are predicted to de- tabase of tree provenance information (St. tions to consider. Reducing fragmentation, cline in productivity due to changes in cli- Clair et al. 2013), and the Climate Change increasing landscape connections, and creat- mate (O’Neill et al. 2008) or pests (Guerrant Tree Atlas is a spatial database containing ing suitable habitats could facilitate “natu- 2012). Listing tree species as candidates for the current and potential status of 134 east- ral” migration (Hoegh-Guldberg et al. assisted migration is a practical first step ern US tree species (Prasad et al. 2007) (Ta- 2008, St. Clair and Howe 2009, Ciccarese et (Hunter 2007, Vitt et al. 2010, Pedlar et al. ble 1). al. 2012). Collecting and storing seed can 2011) but requires a substantial amount of Available habitat, endangered status, also facilitate migration. For example, Al- knowledge about the species and their cur- migration potential, and rotation length are berta is collecting and storing limber pine rent and projected distributions, including considerations in the species selection pro- (Pinus flexilis) and whitebark pine (Pinus al- rotation lengths. The USDA Forest Service cess (McKenney et al. 2009, Vitt et al. bicaulis) seed for reintroduction into current has begun to identify tree species at risk of 2010). Maintaining or improving conserva- ranges or relocation to ranges projected to

Journal of Forestry • July 2013 291 have favorable climate conditions (Pedlar et acres (hectares) to many thousands of square survival, but long enough to ensure adapta- al. 2011). Risk status will change over time miles (kilometers) depending on geographic tion toward the end of a rotation, or lifespan as climatic and landscape conditions change. features. In the western mountains of North of a tree plantation (McKenney et al. 2009). Existing tools and programs (described in America, the environment varies dramati- Therefore, target migration distances are detail in Beardmore and Winder 2011 and cally over very short distances. As a result, needed for short- and long-term planning Friggens et al. 2012) such as the Nature- many narrow, species-specific seed transfer efforts and will require adjustments as new Serve Climate Change Vulnerability Index guidelines and seed zones exist in western climate change information comes to light. (NatureServe 2011), System for Assessing North America relative to fewer, broader Methods using transfer functions and prov- Species Vulnerability (SAVS) (Bagne et al. guidelines and zones in eastern North Amer- enance data have been developed to guide 2011), and Seeds of Success program (Byrne ica (Randall and Berrang 2002). Growth seed movement under climate change (e.g., and Olwell 2008) are available to determine and productivity of most southeastern pines, Beaulieu and Rainville 2005, Wang et al. a species’ risk to climate change (Table 1). for example, are influenced by annual aver- 2006, Crowe and Parker 2008, Thomson et Vulnerability assessments are often the first age minimum temperatures and can be al. 2010, Ukrainetz et al. 2011). Online step in developing adaptation strategies for a transferred to outplanting sites along an tools are available to assist forest managers species (Friggens et al. 2012). east-west gradient and to sites within 5° F and researchers in making decisions about (Ϫ15° C) of their source location (Schmid- matching seedlots with outplanting sites and Target Migration Distance tling 2001). seed transfer (Table 1). The Seedlot Selec- How far we move plant materials to fa- Paramount to any assisted migration ef- tion Tool (Howe et al. 2009) is a mapping cilitate migration will depend on goals fort will be the movement of populations to tool that matches seedlots with outplanting (Figures 1 and 2), the target species and pop- sites that are climatically suitable for growth sites based on current or future climates for ulations, location, projected climatic condi- and productivity at some point in the future tree species such as Douglas-fir, ponderosa tions, and time. Target migration distance is (Pedlar et al. 2011). For a species or popula- pine, and western redcedar, and SeedWhere the distance that populations should be tion, this may entail moving seed across (McKenney et al. 1999) can map out poten- moved to address future climate change and seed-zone boundaries or beyond transfer tial seed collection or outplanting sites based ensure adaptation throughout a tree’s life- guidelines (Ledig and Kitzmiller 1992). As- on climatic similarity of chosen sites to a time (O’Neill et al. 2008). Target migration sisted migration will be best implemented region of interest. Bioclimatic models map- distance can be geographic (e.g., feet or me- where seed transfer guidelines and zones are ping current and projected seed zones have ters along an elevation gradient), climatic currently in place and most successful if also been assessed for aspen (Populus tremu- (e.g., change in number of frost-free days based on climate conditions (McKenney et loides) (Gray et al. 2011); lodgepole (Wang along the same elevational gradient), and/or al. 2009). Provenance data, seed transfer et al. 2006), longleaf (Pinus palustris) (Potter temporal (e.g., date when the current cli- guidelines, and seed zones can be used to and Hargrove 2012), and whitebark pines mate of the migrated population equals the ensure that trees being established today will (McLane and Aitken 2012); dogwood (Cor- future climate of the outplanting site). In be adapted to future climates (Pedlar et al. nus florida) (Potter and Hargrove 2012); and current tree improvement programs, seed 2012). General tree seed transfer guidelines western larch (Rehfeldt and Jaquish 2010). transfer guidelines and zones are used to de- developed by the USDA (McCall et al. Preliminary work in Canada on most com- termine the safest distance that a population 1939) have since improved for commercial mercial tree species demonstrates that target can be moved to avoid maladaptation (John- tree species through provenance trials, but migration distances would be short, occur- son et al. 2004). Transfer functions, derived most are not adjusted for the spatial and ring within current ranges (O’Neill et al. from provenance trials, are used to deter- temporal dynamics associated with contem- 2008, Gray et al. 2011). For some tree spe- mine safe seed transfer distances that are porary climate change. For reforestation cies, target migration distances are then used to delineate geographic boundar- practitioners, this is a major limitation in Ͼ656,168 ft (200 km) north or Ͼ328 ft ies or climatic bands of fixed and focal point making informed decisions about assisted (100 m) up in elevation during the next 20 seed zones (Raymond and Lindgren 1990, migration. Transfer research must factor in to 50 years (Beaulieu and Rainville 2005, McKenney et al. 2009). Because genetic climate change scenarios because plant ma- O’Neill et al. 2008, Pedlar et al. 2012, Gray variation differs by species and location, safe terials guided by current seed transfer guide- and Hamann 2013). The short-distance seed transfer distances also vary. Douglas-fir lines and seed zones might be faced with un- movements, however, may not be adapted has the largest north to south distribution of favorable growing conditions by the end of to their climatic conditions at the end of this any commercial conifer in North America this century. An overwhelming conundrum century (Gray and Hamann 2013). Given and subsequently much local adaptation for assisted migration lies in the matching of the uncertainty in global climate model pre- within populations influenced by elevation, existing plant materials (seed, nursery stock, dictions beyond 2050, it will be difficult to latitude, and longitude (Rehfeldt 1979). or genetic material) with future ecosystems estimate migration distances for long-rota- Across Washington and Oregon, the varia- that have different climate conditions (Pot- tion tree species, but this is not evidence to tion in Douglas-fir changes more rapidly ter and Hargrove 2012). counter the long-term management plan- along an elevational gradient than that of Because long-lived tree species may take ning (Gray and Hamann 2011, Gray et al. western redcedar (Thuja plicata). Thus, safe several decades to reach sexual reproductive 2011). seed transfer distances, in general, will be maturity and many generations to produce much shorter for Douglas-fir than for west- locally adapted genotypes (Ledig et al. 2012, Deployment Strategies ern redcedar (Johnson et al. 2004). Further, Potter and Hargrove 2012), target migra- When and where you plant a long-lived seed zones can range from a few thousand tion distances must be short enough to allow species in a rapidly changing climate may be

292 Journal of Forestry • July 2013 one of the most significant and perplexing climatic modeling and multivariate ap- vide opportunities to breed and select for components of assisted migration (Mc- proaches to identify the best matching seed traits, such as drought tolerance (St. Clair Donald-Madden et al. 2011). Maladapta- sources for current and projected climates and Howe 2009). Allowing for physiological tion may occur if a species is introduced too (2020, 2050, and 2080) in Alberta. Al- or morphological variation in nursery stock soon to its “new” environment, or a species though they encourage the use of identified might serve to facilitate natural selection to may competitively interact with other spe- seed sources for current and 2020 projec- future climates, more so than planting stock cies, causing loss of ecosystem function or tions, they discourage using seed sources that has uniformity in traits (Anderson and structure (Aubin et al. 2011). Optimal tim- identified for 2050 and 2080 because of the Chmura 2009). ing will depend on the target population, high uncertainty with climate modeling. Commercial tree species have a long cost, and carrying capacity of seed source Composite provenancing (Broadhurst et al. history of human-assisted propagation; and outplanting locations (McDonald- 2008) is the collection of seed near the out- therefore, site selection will be largely deter- Madden et al. 2011). Assisted migration ex- planting site and from distant but climati- mined by harvest and reforestation opera- periments coupled with projected climate cally similar sites. It prescribes collecting tions (and, by their very nature, produce change may help determine the best time to from populations of increasing distance in outplanting sites) (Pedlar et al. 2011). Cur- deploy plant materials (Lawler and Olden an attempt to mimic gene flow patterns in rent and projected seed zones generated 2011). Outplanting at high densities can al- the direction of predicted climate change from bioclimatic models in GIS can identify low for natural and artificial selection by (Breed et al. 2012). Both predictive and suitable outplanting sites. SeedWhere (Mc- thinning, thereby removing the maladapted composite provenancing require population Kenney et al. 1999) and the Seedlot Selec- or slow-growing trees (St. Clair and Howe growth and genetic information coupled tion Tool (Howe et al. 2009) operate a focal 2009), however with the downside of higher with climate change projections. point seed zone system that rates climatic costs. Where we lack genetic information and similarity between a planting site and a pop- Existing reforestation guidelines focus associated climatic model projections for ulation’s distribution across a region of in- on using local seed sources because they are target tree populations, admixture prov- terest in North America. Output maps allow best adapted to the local conditions (Kramer enancing (Breed et al. 2012), climatic users to view and choose desired levels of and Havens 2009). In the context of climate matching of outplanting site with seed climatic conditions for seed collection or change, however, “local” becomes irrele- source (McKenney et al. 2009), and broad- outplanting (McKenney et al. 2009). Cre- vant. A key challenge in forestry is to develop ening of collection guidelines to capture a ation of outplanting sites might be necessary an adaptive program that conserves the evo- diversity of genotypes from various environ- for species and populations at moderate or lutionary potential of a tree species and/or ments (Broadhurst et al. 2008) can increase high risk of decline (Hoegh-Guldberg et al. population, which relates directly to seed se- a population’s chance for adaptation in as- 2008, Aubin et al. 2011). Use of disturbed lection, production, and collection (Crowe sisted migration efforts. Admixture prov- areas as outplanting sites to test assisted mi- and Parker 2008). The goal is to select and enancing (Breed et al. 2012) is the collection gration is another option, especially where a deploy seed sources adapted to future cli- of seed from a large population across differ- species or population is experiencing habitat mate conditions at target outplanting sites, ent environments with no spatial bias to the loss (Jones and Monaco 2009, Aubin et al. i.e., seed sources that show the least amount outplanting site. Guidelines that focus on 2011). Soil surveys and ecological site de- of maladaptation and outbreeding and in- increasing the genetic diversity within the scriptions provide additional support in site breeding depression over time (Breed et al. deployment population provide some long- selection (Herrick et al. 2006). 2012). To alleviate concerns about suitabil- term insurance that would counter against ity of local populations as seed sources, uncertainty in climate predictions and spe- Maintenance and Monitoring Breed et al. (2012) developed a seed source cies reactions to climate change (Ledig and Throughout the entire assisted migra- (provenance) decision framework, in which Kitzmiller 1992, St. Clair and Howe 2009, tion process, careful documentation is criti- strategies (predictive, composite, and ad- Vitt et al. 2010), although extremely high cal. All assisted migration efforts should start mixture provenancing) are selected based on levels of diversity may swamp the few indi- with species and provenance information— climate change projections and level of ge- viduals in a collection that are adapted to location and size of seed source and popula- netic and environmental information about either the current or future climate condi- tion, outplanting design (date and density), a population. Predictive provenancing (Sgro` tions (Falk et al. 2001). Therefore, the level outplanting location (climate, aspect, slope, et al. 2011) couples population growth data of diversity should match the level of climate and site preparation), and assessment of sur- with climate change and bioclimatic models uncertainty. Seed from tree seed orchards vival and recruitment (Breed et al. 2012). to identify genotypes adapted to future cli- might be favored over local and natural Postestablishment maintenance, such as matic conditions (e.g., Beaulieu and Rain- sources because these trees have been se- herbicide application and pest/predation ville 2005, Crowe and Parker 2008, Reh- lected to produce offspring that perform control, can be used to help plants establish. feldt and Jaquish 2010, Wang et al. 2010). well across a large geographic area (Randall Measures that determine success, such as When done correctly, predictive provenanc- and Berrang 2002), but it is not clear how growth standards, reproductive fitness or ing can reduce maladaptation, but there is climate change will affect seed production ability, ecosystem health assessments, and high uncertainty in climate forecasts beyond over time for each species (Pedlar et al. degree of invasiveness will be critical to as- 2050 such that if climate change predictions 2011). Provisional seed zones can also be sisted migration efforts (Aubin et al. 2011, are incorrect, selected genotypes may fail to used to select deployment areas for species Winder et al. 2011, Pedlar et al. 2012). establish (Aubin et al. 2011, Breed et al. and populations (Table 1). Tree improve- Short-term (first few months to 1 year) and 2012). Gray and Hamann (2011) used bio- ment programs in North America can pro- long-term (Ͼ3 years) monitoring of survival

Journal of Forestry • July 2013 293 and growth will provide valuable feedback als) can provide valuable information and mountain pine beetle outbreaks in the about target plant characteristics and mea- feedback to assisted migration frameworks Rocky Mountains on lodgepole pine popu- sures for success to nursery and land manag- (Pedlar et al. 2011, Park and Talbot 2012). lations, for example, are accelerated by warm ers (Landis et al. 2010). A lag in response A way to address uncertainty in climate temperatures and low precipitation to such time to both climate change and assisted mi- change forecasts is to conserve and/or maxi- an extent that even changes in management gration will make it especially difficult to de- mize genetic and geographic diversity in cannot curtail their impact (Regniere and termine success, in addition to the fact that plant materials (Ledig and Kitzmiller 1992, Bentz 2008). the ecological consequences of assisted mi- Sgro` et al. 2011). Diversity is an insurance gration on recipient ecosystems may be de- policy, providing populations with adaptive Conclusion layed and/or difficult to measure. Projects and evolutionary abilities to offset climate Forest management and conservation may need long-term intervention due to un- change (Lynch and Walsh 1998). Genetic plans need to incorporate climate change re- certainties about the impact of a species mi- diversity can be conserved by protecting nat- search as it becomes available (Peters and gration. Monitoring will provide valuable ural reserves in heterogeneous landscapes, Darling 1985). We can predict with some information about tree response and provide through provenance and seed source tests, certainty how species, populations, and eco- feedback to decision frameworks. and collecting seed from many populations systems will be affected by climate change across their geographic range for long-term (Chmura et al. 2011), and adaptive frame- Additional Considerations storage (St. Clair and Howe 2009, Sgro` et al. works that lead to action are pertinent The biological, operational, and ad- 2011). A seed collection from high-elevation (McLachlan et al. 2007, Lawler and Olden ministrative tradeoffs are vital consider- seed zones could also be supplemented with 2011, Park and Talbot 2012). Ultimately ations in development of target migration seeds from a lower-elevation seed zone, with our capacity to implement assisted migra- distances for future climate scenarios. Cost the assumption that the higher-elevation tion will be limited by politics, cost, loca- will increase as the number of seed zones sites will become warmer due to climate tion, and time; however, synthesizing what increases relative to seed and nursery pro- change (Friggens et al. 2012). we already know about plant adaptation and duction (stock, storage, and delivery), along Assisted migration may not be appro- climate change is a necessary start. Target with the increased burden of administrative priate for every species, population, or eco- migration distances can be estimated with regulations, and recordkeeping (Lindgren system. Changes in climate are increasing provenance data (e.g., adaptive traits and and Ying 2000). The lack of target migra- the likelihood, frequency, and intensity of geographic and climatic characteristics) and tion distances is a major limitation in mak- extreme weather events, such as heat waves, modeling tools, but we need researchers to ing informed decisions about assisted migra- floods, and drought (Walsh et al. 2013). collaborate and incorporate data into a cen- tion, given the uncertainty about which Over most of the United States, heat waves tral warehouse (e.g., Center for Forest Prov- climate to prepare for. This brings to light will be a common occurrence (Karl et al. enance Data; Table 1). Most importantly, the spatial and temporal challenges associ- 2008), contributing to drought and wild- land managers testing new adaptation strat- ated with assisted migration and climate fires (Trenberth 2011). Climate change ef- egies must share their successes and failures change adaptation strategies in general. fects might be so abrupt that assisted migra- across landscapes, regions, and agencies and Managers should prepare for all climate sce- tion may not be an option, even within a provide feedback to adaptive management narios (Park and Talbot 2012), but with sev- species’ current range. Reductions in fire fre- plans. The key to long-term success is the eral emissions scenarios (IPCC 2000) and quency from 100 to 300 years to 30 years, integration of current research with both many global climate models (IPCC 2007), for example, have the potential to quickly short and long-term experiments. this is an overwhelming task, even in light of shift some forest systems to woodlands and new scenarios and models in the forthcom- grasslands (Westerling et al. 2011), thereby Literature Cited ing IPCC Assessment Report (IPCC 2013). reducing the availability of genetic resources AITKEN, S.N., S. YEAMAN, J.A. HOLLIDAY,T. Climate change projections are developed at needed to move tree populations. By 2100, WANG, AND S. CURTIS-MCLANE. 2008. Adap- broader spatial and temporal scales than an estimated 55% of landscapes in the west- tation, migration or extirpation: Climate land management planning, but managers ern United States may exhibit climates that change outcomes for tree populations. Evol. Appl. 1:95–111. can refer to downscaled output scenarios are incompatible with vegetation ecosystems ANDERSON, P.D., AND D.J. CHMURA. 2009. Sil- specific to local regions to help understand occurring there today (Rehfeldt et al. 2006). vicultural approaches to maintain forest health the range of possibilities (Daniels et al. Evaluation of complementary actions, such and productivity under current and future cli- 2012). Further, projected scenarios can be as ecosystem engineering (e.g., using drasti- mates. West. For. 54(1):6–8. combined into consensus maps showing cally disturbed areas as sites to test assisted AUBIN, I., C.M. GARBE,S.COLOMBO, C.R. agreements, which have been demonstrated migration) and landscape connectivity (e.g., DREVER, D.W. MCKENNEY,C.MESSIER, J. PEDLAR, ET AL. 2011. Why we disagree about for Brewer spruce (Picea breweriana) (Ledig reduce fragmentation) are warranted (Jones assisted migration: Ethical implications of a et al. 2012) and Douglas-fir (Wang et al. and Monaco 2009, Seddon 2010, Lawler key debate regarding the future of Canada’s 2012). and Olden 2011). Notwithstanding, plant forests. For. Chron. 87:755–765. Small-scale experiments, such as out- survival may be more determined by avail- BAGNE, K.E., M.M. FRIGGENS, AND D.M. FINCH. planting of fast-growing trees adapted to ability of suitable recipient ecosystems (Au- 2011. A system for assessing vulnerability of spe- projected climate in the next 15–30 years or bin et al. 2011), existence of landscape con- cies (SAVS) to climate change. USDA For. Serv., Gen. Tech. Rep. RMRS-GTR-257, Fort Col- randomly outplanting a variety of seed nections needed for plants to move (Hannah lins, CO. 28 p. sources in one area and monitoring their 2008), and intensity of insect outbreaks (Lo- BEARDMORE, T., AND R. WINDER. 2011. Review adaptive response (similar to provenance tri- gan et al. 2003, Bentz et al. 2010). The of science-based assessments of species vulner-

294 Journal of Forestry • July 2013 ability: Contributions to decision-making for toration under climate change scenarios. Cli- guide for the northeastern United States. Ma- assisted migration. For. Chron. 87:745–754. matic Change 89:355–370. nomet Center for Conservation Sciences, Rep. BEAULIEU, J. 2009. Optisource: A tool for optimiz- DANIELS, A.E., J.F. MORRISON, L.A. JOYCE, N.L. NCI-2009-1, Brunswick, ME. 16 p. ing seed transfer. Canadian Forest Service, CROOKSTON, S.C. CHEN, AND S.G. MCNULTY. HANNAH, L. 2008. Protected areas and climate Ottawa, ON, Canada. 2 p. 2012. Climate projections FAQ. USDA For. change. Ann. N.Y. Acad. Sci. 1134:201–212. BEAULIEU, J., AND A. RAINVILLE. 2005. Adapta- Serv., Gen. Tech. Rep. RMRS-GTR-277, HERRICK, J.E., G.E. SCHUMAN, AND A. RANGOA. tion to climate change: Genetic variation is Fort Collins, CO. 32 p. 2006. Monitoring ecological processes for res- both a short- and a long-term solution. For. DAVIS, M.B., AND R.G. SHAW. 2001. Range shifts toration projects. J. Nat. Conserv. 14:161–171. Chron. 81:704–709. and adaptive responses to quaternary climate HEWITT, N., N. KLENK, A.L. SMITH, D.R. BA- BENTZ, B.J., J. RE´GNIE`RE, C.J. FETTIG, E.M. change. Science 292:673–679. ZELY,N.YAN,S.WOOD, J.I. MACLELLAN,C. HANSEN, J.L. HAYES, J.A. HICKE, R.G. KELSEY, DUMROESE, R.K., T.D. LANDIS, AND T. LUNA. LIPSIG-MUMME, AND I. HENRIQUES. 2011. J.F. NEGROŃ, AND S.J. SEYBOLD. 2010. Cli- 2012. Raising native plants in nurseries: Basic Taking stock of the assisted migration debate. mate change and bark beetles of the Western concepts. USDA For. Serv., Gen. Tech. Rep. Bio. Conserv. 144:2560–2572. United States and Canada: Direct and indirect RMRS-GTR-274, Fort Collins, CO. 92 p. HOEGH-GULDBERG, O., L. HUGHES,S.MCIN- effects. BioScience 60:602–613. DUMROESE, R.K., T. LUNA, AND T.D. LANDIS. TYRE, D.B. LINDENMAYER,C.PARMESAN, H.P. BIERBAUM, R., J.B. SMITH,A.LEE,M.BLAIR,L. 2009. Nursery manual for native plants: A guide POSSINGHAM, AND C.D. THOMAS. 2008. As- CARTER, F.S. CHAPIN,P.FLEMING, ET AL. for tribal nurseries. USDA For. Serv., Agr. sisted colonization and rapid climate change. 2013. A comprehensive review of climate ad- Handbk. 730, Washington, DC. 302 p. Science 321:345–346. aptation in the United States: More than be- ERICKSON, V.J., C. AUBRY, P.C. BERRANG,T. HOWE, G.T., J.B. ST.CLAIR, AND R. BELOIN. fore, but less than needed. Mitig. Adapt. BLUSH, A.D. BOWER, B.S. CRANE,T.DESPAIN, 2009. Seedlot Selection Tool. Available online at Strateg. Global Change 18:361–406. ET AL. 2012. Genetic resource management and sst.forestry.oregonstate.edu/contact_us.html; BONNER, F.T., R.P. KARRFALT, AND R.G. NISLEY. climate change: Genetic options for adapting na- last accessed Jan. 3, 2013. 2008. The woody plant seed manual. USDA tional forests to climate change. USDA For. HUNTER, M.L. JR. 2007. Climate change and For. Serv., Agr. Handbk. 727, Washington, Serv., Forest Management, Washington, DC. moving species: Furthering the debate on as- DC. 1223 p. 24 p. sisted colonization. Conserv. Biol. 21:1356– BREED, M.F., M.G. STEAD, K.M. OTTEWELL, FALK, D.A., E.E. KNAPP, AND E.O. GUERRANT JR. 1358. M.G. GARDNER, AND A.J. LOWE. 2012. Which 2001. An introduction to restoration genetics. INTERGOVERNMENTAL PANEL ON CLIMATE provenance and where? Seed sourcing strate- Society for Ecological Restoration, Washing- CHANGE. 2000. Special report emissions scenar- gies for revegetation in a changing environ- ton, DC. 33 p. ios: Summary for policymakers. Available online ment. Conserv. Genet. 14:1–10. FINCH, D.M. 2012. Climate change in grasslands, at www.grida.no/publications/other/ipcc_sr/ BRESHEARS, D.D., N.S. COBB, P.M. RICH, K.P. shrublands, and deserts of the interior American ?srcϭ/climate/ipcc/emission/; last accessed PRICE, C.D. ALLEN, R.G. BALICE, W.H. West: A review and needs assessment. USDA June 24, 2013. ROMME, ET AL. 2005. Regional vegetation die- For. Serv., Gen. Tech. Rep. RMRS-GTR-285, INTERGOVERNMENTAL PANEL ON CLIMATE off in response to global-change-type drought. Fort Collins, CO. 139 p. CHANGE. 2007. Climate change 2007: The Proc. Natl. Acad. Sci. USA 102:15144–15148. FRIGGENS, M.M., J.R. PINTO, R.K. DUMROESE, physical science basis. Available online at BROADHURST, L.M., A. LOWE, D.J. COATES, S.A. AND N.L. SHAW. 2012. Decision support: Vul- www.ipcc.ch/publications_and_data/ar4/ CUNNINGHAM,M.MCDONALD, P.A. VESK, nerability, conservation, and restoration. P. wg1/en/contents.html; last accessed June 24, AND C. YATES. 2008. Seed supply for broad- 116–139 in Climate change in grasslands, shru- 2013. scale restoration: Maximizing evolutionary po- blands, and deserts of the interior American West: INTERGOVERNMENTAL PANEL ON CLIMATE tential. Evol. Appl. 1:587–597. A review and needs assessment, Finch, D.M. CHANGE. 2013. Activities: Fifth assessment re- BYRNE, M.K., AND P. OLWELL. 2008. Seeds of (ed.). USDA For. Serv., Gen. Tech. Rep. port. Available online at www.ipcc.ch/ success: The national native seed collection RMRS-GTR-285, Fort Collins, CO. activities/activities.shtml#.UZviqqLvvTo; last program in the United States. Publ. Gardens GRAY, L.K., T. GYLANDER, M.S. MBOGGA,P. accessed June 24, 2013. 23:3–4. CHEN, AND A. HAMANN. 2011. Assisted migra- JANSEN, E., J. OVERPECK, K.R. BRIFFA, J.-C. DU- CAMPBELL, R.K. 1974. Use of phenology for ex- tion to address climate change: Recommenda- PLESSY,F.JOOS,V.MASSON-DELMOTTE,D. amining provenance transfers in reforestation tions for aspen reforestation in western Can- OLAGO, ET AL. 2007. Palaeoclimate. P. 433– of Douglas-fir. J. Appl. Ecol. 11:1069–1080. ada. Ecol. Appl. 21:1591–1603. 498 in Climate change 2007: The physical sci- CAMPBELL, R.K. 1979. Genecology of Douglas- GRAY, L.K., AND A. HAMANN. 2011. Strategies for ence basis, Solomon, S., D. Qin, M. Manning, fir in a watershed in the Oregon Cascades. reforestation under uncertain future climates: Z. Chen, M. Marquis, K.B. Averyt, M. Ecology 60:1036–1050. Guidelines for Alberta, Canada. PLoS One Tignor, and H.L. Miller (eds.). Cambridge CAMPBELL, R.K. 1986. Mapped genetic variation 6:1–9. University Press, Cambridge, UK. of Douglas-fir to guide seed transfer in south- GRAY, L.K., AND A. HAMANN. 2013. Tracking JOHNSON, G.R., F.C. SORENSEN, J.B. ST.CLAIR, west Oregon. Silv. Genet. 35:2–3. suitable habitat for tree populations under cli- AND R.C. CRONN. 2004. Pacific northwest for- CHMURA, D.J., P.D. ANDERSON, G.T. HOWE, mate change in western North America. Cli- est tree seed zones: A template for native C.A. HARRINGTON, J.E. HALOFSKY, D.L. matic Change 117:289–303. plants? Native Plants J. 131–140. PETERSON, D.C. SHAW, AND J.B. ST.CLAIR. GROFFMAN, P.M., P. KAREIVA,S.CARTER, N.B. JOHNSON, R., S. BOYCE,L.BRANDT,V.ERICKSON, 2011. Forest responses to climate change in GRIMM, J.J. LAWLER,M.MACK,V.MATZEK, L. IVERSON,G.KUJAWA,L.STRITCH, AND B. the northwestern United States: Ecophysi- AND H. TALLIS. 2013. Ecosystems. P. 291–330 TKACZ. 2013. Policy and strategy considerations ological foundations for adaptive manage- in NCADAC draft climate assessment report.US for assisted migration on USDA Forest Service ment. For. Ecol. Manage. 261:1121–1142. Global Change Research Program, Washing- lands. Proc. of the 60th Western international forest CHUINE, I. 2010. Why does phenology drive spe- ton, DC. disease work conference (WIFDWC), Browing, J. cies distribution? Philos. Trans. R. Soc. Lond. B GUERRANT, E.O. JR. 2012. Characterizing two (ed.). Lake Tahoe, CA. In press. Biol. Sci. 365:3149–3160. decades of rare plant reintroductions. P. 9–29 JONES, T.A., AND T.A. MONACO. 2009. A role for CICCARESE, L., A. MATTSSON, AND D. in Plant reintroduction in a changing climate: assisted evolution in designing native plant PETTENELLA. 2012. Ecosystem services from Promises and perils, Maschinski, J., and K.E. materials for domesticated landscapes. Front. forest restoration: Thinking ahead. New For. Haskins (eds.). Island Press, Washington, DC. Ecol. Environ. 7:541–547. 43:543–560. GUNN, J.S., J.M. HAGAN, AND A.A. WHITMAN. JOYCE, L.A., S.W. RUNNING, D.D. BRESHEARS, CROWE, K.A., AND W.H. PARKER. 2008. Using 2009. Forestry adaptation and mitigation in a V.H. DALE, R.W. MALMSHEIMER, R.N. SAMP- portfolio theory to guide reforestation and res- changing climate—A forest resource manager’s SON,B.SOHNGEN, AND C.W. WOODALL.

Journal of Forestry • July 2013 295 2013. Forestry. P. 263–289 in NCADAC tion during the 20th century. Science 320: NOTARO, M., A. MAUSS, AND J.W. WILLIAMS. Draft Climate Assessment Report. US Global 1768–1771. 2012. Projected vegetation changes for the Change Research Program, Washington, DC. LINDGREN, D., AND C.C. YING. 2000. A model American Southwest: Combined dynamic JUMP, A.S., AND J. PENUELAS. 2005. Running to integrating seed source adaptation and seed modeling and bioclimatic-envelope approach. stand still: Adaptation and the response of use. New For. 20:87–104. Ecol. Appl. 22:1365–1388. plants to rapid climate change. Ecol. Lett. LO, Y., J.A. BLANCO, J.P. KIMMINS,B.SEELY, AND O’NEILL, G.A., N.K. UKRAINETZ,M.CARLSON, 8:1010–1020. C. WELHAM. 2011. Linking climate change C. CARTWRIGHT,B.JAQUISH,J.KING,J.KRA- JUMP, A.S., C. MATYAS, AND J. PENUELAS. 2009. and forest ecophysiology to project future KOWSKI, ET AL. 2008. Assisted migration to ad- The altitude-for-latitude disparity in the range trends in tree growth: A review of forest mod- dress climate change in British Columbia: Rec- retractions of woody species. Trends Ecol. Evol. els. P. 63–87 in Climate change research and ommendations for interim seed transfer 24(12):694–701. technology for adaptation and mitigation, standards. BC Ministry of Forestry and Range, KARL, T.R., G.A. MEEHL, T.C. PETERSON, K.E. Blanco, J. (eds.). InTech, Rijeka, Croatia. Tech. Rep. 048, Victoria, BC, Canada. 38 p. UNKEL UTOWSKI AND AST K , J.W.J. G , D.R. E - LOGAN, J.A., J. REGNIERE, AND J.A. POWELL. PARK, A., AND C. TALBOT. 2012. Assisted migra- ERLING. 2008. Weather and climate extremes 2003. Assessing the impacts of global warming tion: Uncertainty, risk and opportunity. For. in a changing climate: North America, Ha- on forest pest dynamics. Front. Ecol. Environ. Chron. 88:412–419. waii, Caribbean, and US Pacific Islands, 1:130–137. PARMESAN, C. 2007. Influences of species, lati- Karl, T.R., G.A. Meehl, C.D. Miller, S.J. LYNCH, M., AND B. WALSH. 1998. Genetics and tudes and methodologies on estimates of phe- Hassol, A.M. Waple, and W.L. Murray analysis of quantitative traits. Sinauer Assoc., nological response to global warming. Global (eds.). US Climate Change Science Program Inc., Sunderland, MA. 980 p. Change Biol. 13(9):1860–1872. and the Subcommittee on Global Change MARRIS, E. 2009. Planting the forest for the fu- Research, Washington, DC. PEDLAR, J., D.W. MCKENNEY,J.BEAULIEU,S. ture. Nature 459:906–908. COLOMBO, J.S. MCLACHLAN, AND G.A. KRAMER, A.T., AND K. HAVENS. 2009. Plant con- MASCHINSKI, J., AND K.E. HASKINS. 2012. Plant O’NEILL. 2011. The implementation of as- servation genetics in a changing world. Trends reintroduction in a changing climate: Promises Plant. Sci. 14:599–607. sisted migration in Canadian forests. For. and perils. Island Press, Washington, DC. Chron. 87:766–777. LANDIS, T.D., R.K. DUMROESE, AND D.L. HAASE. 402 p. 2010. The container tree nursery manual: Seed- PEDLAR, J., D.W. MCKENNEY,I.AUBIN,T. MCCALL, M.A., F.A. SILCOX, D.S. MYER, AND ling processing, storage, and outplanting, vol. 7. BEARDMORE,J.BEAULIEU, L.R. IVERSON, G.A. H.A. WALLACE. 1939. Forest policy of US De- O’NEILL, R.S. WINDER, AND C. STE-MARIE. USDA For. Serv., Agr. Handbk. 674, Fort partment of Agriculture. J. For. 37:820–821. Collins, CO. 192 p. 2012. Placing forestry in the assisted migration MCDONALD-MADDEN, E., M.C. RUNGE, H.P. LANDIS, T.D., R.W. TINUS, AND J.P. BARNETT. debate. BioScience 62:835–842. POSSINGHAM, AND T.G. MARTIN. 2011. Opti- 1998. The container tree nursery manual: Seed- PETERS, R.L., AND J.D.S. DARLING. 1985. The mal timing for managed relocation of species ling propagation, vol. 6. USDA For. Serv., Agr. greenhouse-effect and nature reserves. BioSci- faced with climate change. Nat. Clim. Change Handbk. 674, Fort Collins, CO. 166 p. ence 35:707–717. 1:261–265. LANDIS, T.D., R.W. TINUS, S.E. MCDONALD, PHILLIPS, S.J., R.P. ANDERSON, AND R.E. SCHA- MCKENNEY, D.W., B.G. MACKEY, AND D. JOYCE. AND J.P. BARNETT. 1989. The container tree PIRE. 2006. Maximum entropy modeling of 1999. Seedwhere: A computer tool to support nursery manual: Seedling nutrition and irriga- species geographic distributions. Ecol. Model. seed transfer and ecological restoration deci- tion, vol. 4. USDA For. Serv., Agr. Handbk. 190:231–259. sions. Environ. Model. 14:589–595. 674, Fort Collins, CO. 119 p. POTTER, K.M., AND W.W. HARGROVE. 2012. MCKENNEY, D.W., J. PEDLAR, AND G.A. LANGLET, O. 1971. Two hundred years genecol- Determining suitable locations for seed trans- ogy. Taxon 20(5/6):653–721. O’NEILL. 2009. Climate change and forest seed zones: Past trends, future prospects and fer under climate change: A global quantitative LAWLER, J.J., AND J.D. OLDEN. 2011. Reframing method. New For. 43:581–599. the debate over assisted colonization. Front. challenges to ponder. For. Chron. 85:258– 265. PRASAD, A.M., L.R. IVERSON,S.MATTHEWS, AND Ecol. Environ. 9:569–574. M. PETERS. 2007. A climate change atlas for 134 MCLACHLAN, J.S., J.J. HELLMANN, AND M.W. LEDIG, F.T., AND J.H. KITZMILLER. 1992. Ge- forest tree species of the Eastern United States. netic strategies for reforestation in the face of SCHWARTZ. 2007. A framework for debate of assisted migration in an era of climate change. Available online at www.nrs.fs.fed.us/atlas/ global climate change. For. Ecol. Manage. 50: tree/tree_atlas.html; last accessed Feb. 1, 2013. 153–169. Conserv. Biol. 21:297–302. RANDALL, W.K., AND P.C. BERRANG. 2002. LEDIG, F.T., G.E. REHFELDT, AND B. JAQUISH. MCLANE, S.C., AND S.N. AITKEN. 2012. White- bark pine (Pinus albicaulis) assisted migration Washington tree seed transfer zones. Washing- 2012. Projections of suitable habitat under cli- ton Department of Natural Resources, Olym- mate change scenarios: Implications for trans- potential: Testing establishment north of the pia, WA. 84 p. boundary assisted colonization. Am. J. Bot. 99: species range. Ecol. Appl. 22:142–153. RAYMOND, C.A., AND D. LINDGREN. 1990. Ge- 1217–1230. MICHAELIAN, M., E.H. HOGG, R.J. HALL, AND E. netic flexibility—A model for determining the LEITES, L.P., A.P. ROBINSON, G.E. REHFELDT, ARSENAULT. 2011. Massive mortality of aspen range of suitable environments for a seed J.D. MARSHALL, AND N.L. CROOKSTON. 2012. following severe drought along the southern Height-growth response to climate changes edge of the Canadian boreal forest. Global source. Silv. Genet. 39:112–120. differs among populations of Douglas-fir: A Change Biol. 17:2084–2094. REGNIERE, J., AND B. BENTZ. 2008. Mountain novel analysis of historic data. Ecol. Appl. 22: MORGENSTERN, E.K. 1996. Geographic variation pine beetle and climate change. P. 63–64 in 154–165. in forest trees: Genetic basis and application of Proc. 19th US Department of Agriculture Inter- LEMPRIERE, T.C., P.Y. BERNIER, A.L. CARROLL, knowledge in silviculture. UBC Press, Vancou- agency research forum on invasive species. USDA M.D. FLANNIGAN, R.P. GILSENAN, D.W. ver, BC, Canada. 206 p. For. Serv., Gen. Tech. Rep. NRS-P-36, New- MCKENNEY, E.H. HOGG,J.PEDLAR, AND D. MUELLER, J.M., AND J.J. HELLMANN. 2008. An town Square, PA. BLAIN. 2008. The importance of forest sector ad- assessment of invasion risk from assisted mi- REGNIERE, J., AND R. SAINT-AMANT. 2008. Bio- aptation to climate change. North. For. Centre, gration. Conserv. Biol. 22:562–567. SIM 9—User’s manual. Laurentian For. Cen- Info. Rep. NOR-X-416E, Natural Resources NATURESERVE. 2011. NatureServe mission. Avail- tre, Info. Rep. LAU-X-134:76, Natural Re- Canada, Canadian Forest Service, Edmonton, able online at www.natureserve.org/aboutUs/ sources Canada, Canadian Forest Service. AB, Canada. 78 p. index.jsp; last accessed June 24, 2013. REHFELDT, G.E. 1979. Ecological adaptations in LENOIR, J., J.C. GEGOUT, P.A. MARQUET,P.DE NATURAL RESOURCES CANADA. 2013. Assisted mi- Douglas-fir (Pseudotsuga menziesii var. Glauca) RUFFRAY, AND H. BRISSE. 2008. A significant gration. Available online at cfs.nrcan.gc.ca/ populations. I. North Idaho and North-East upward shift in plant species optimum eleva- pages/367; last accessed June 24, 2013. Washington. Heredity 43:383–397.

296 Journal of Forestry • July 2013 REHFELDT, G.E. 1983. Ecological adaptations in toration. Society for Ecological Restoration USDA FOREST SERVICE. 2008. Forest Service stra- Douglas-fir (Pseudotsuga menziesii var. Glauca) Tucson, AZ. 15 p. tegic framework for responding to climate change. populations. III. Central Idaho. Can. J. For. SGRO` , C.M., A.J. LOWE, AND A.A. HOFFMANN. Washington, DC. 21 p. Res. 13:626–632. 2011. Building evolutionary resilience for con- VITT, P., K. HAVENS, A.T. KRAMER,D.SOLLEN- REHFELDT, G.E., AND B.C. JAQUISH. 2010. Eco- serving biodiversity under climate change. BERGER, AND E. YATES. 2010. Assisted migra- logical impacts and management strategies for Evol. Appl. 4:326–337. tion of plants: Changes in latitudes, changes in western larch in the face of climate-change. ST.CLAIR, J.B., AND G.T. HOWE. 2009. Genetic attitudes. Biol. Conserv. 143:18–27. Mitig. Adapt. Strat. Global Change 15:283– options for adapting forests to climate change. WALSH, J., D. WUEBBLES,K.HAYHOE,K.KUN- 306. West. For. January/February:9–11. KEL,R.SOMERVILLE,G.STEPHENS,P.THORNE, REHFELDT, G.E., N.L. CROOKSTON, M.V. WAR- ST.CLAIR, J.B., G.T. HOWE,J.WRIGHT, AND R. ET AL. 2013. Our changing climate. P. 25–103 WELL, AND J.S. EVANS. 2006. Empirical analy- BELOIN. 2013. Center for Forest Provenance in NCADAC draft climate assessment report.US sis of plant-climate relationships for the west- Data. Available online at cenforgen.forestry. Global Change Research Program, Washing- ern United States. Int. J. Plant Sci. 167:1123– oregonstate.edu/contact_us.php; last accessed ton, DC. 1150. June 24, 2013. WANG, T., G.A. O’NEILL, AND S.N. AITKEN. RICCIARDI, A., AND D. SIMBERLOFF. 2009. As- STE-MARIE, C., E.A. NELSON,A.DABROS, AND 2010. Integrating environmental and genetic sisted colonization is not a viable conservation M. BONNEAU. 2011. Assisted migration: Intro- effects to predict responses to tree populations strategy. Trends Ecol. Evol. 24(5):248–253. duction to a multifaceted concept. For. Chron. to climate. Ecol. Appl. 20:153–163. RICHARDSON, D.M., J.J. HELLMANN, J.S. 87:724–730. WANG, T., E.M. CAMPBELL, G.A. O’NEILL, AND MCLACHLAN, D.F. SAX, M.W. SCHWARTZ,P. TRENBERTH, K.E. 2011. Changes in precipitation S.N. AITKEN. 2012. Projecting future distribu- GONZALEZ, E.J. BRENNAN, ET AL. 2009. Mul- with climate change. Climate Res. 47:123. tions of ecosystem climate niches: Uncertain- tidimensional evaluation of managed reloca- THOMSON, A.M., K.A. CROW, AND W.H. ties and management applications. For. Ecol. tion. Proc. Natl. Acad. Sci. USA 106:9721– PARKER. 2010. Optimal white spruce breeding Manage. 279:128–140. 9724. zones for Ontario under current and future WANG, T., A. HAMANN,A.YANCHUK, G.A. SCHMIDTLING, R.C. 2001. Southern pine seed climates. Can. J. For. Res. 40:1576–1587. O’NEILL, AND S.N. AITKEN. 2006. Use of resources. USDA For. Serv., Gen. Tech. Rep. TORREYA GUARDIANS. 2012. Assisted migration sponse functions in selecting lodgepole pine GTR-SRS-44, Asheville, NC. 35 p. (assisted colonization, managed relocation) and populations for future climates. Global Change SCHWARTZ, M.W. 1994. Conflicting goals for rewilding of plants and animals in an era of Biol. 12:2404–2416. conserving biodiversity: Issues of scale and global warming. Available online at www. WESTERLING, A.L., M.G. TURNER, E.A.H. value. Nat. Areas J. 14:213–216. torreyaguardians.org/assisted-migration.html; SMITHWICK, W.H. ROMME, AND M.G. RYAN. SCHWARTZ, M.W., J.J. HELLMANN, J.M. last accessed June 24, 2013. 2011. Continued warming could transform MCLACHLAN, D.F. SAX, J.O. BOREVITZ,J. UKRAINETZ, N.K., G.A. O’NEILL, AND B.C. Greater Yellowstone fire regimes by mid-21st BRENNAN, A.E. CAMACHO, ET AL. 2012. Man- JAQUISH. 2011. Comparison of fixed and focal century. Proc. Natl. Acad. Sci. USA 108(32): aged relocation: Integrating the scientific, reg- point seed transfer systems for reforestation 13165–13170. ulatory, and ethical challenges. BioScience 62: and assisted migration: A case study for inte- WINDER, R., E.A. NELSON, AND T. BEARDMORE. 732–743. rior spruce in British Columbia. Can. J. For. 2011. Ecological implications for assisted mi- SEDDON, P.J. 2010. From reintroduction to as- Res. 41:1452–1464. gration in Canadian forests. For. Chron. 87: sisted colonization: Moving along the conser- US ENVIRONMENTAL PROTECTION AGENCY. 731–744. vation translocation spectrum. Restor. Ecol. 18: 2010. Climate change indicators in the United ZHU, K., C.W. WOODALL, AND J.S. CLARK. 2012. 796–802. States. Available online at www.epa.gov/ Failure to migrate: Lack of tree range expan- SOCIETY FOR ECOLOGICAL RESTORATION. 2004. climatechange/indicators.html; last accessed sion in response to climate change. Global The SER international primer on ecological res- June 24, 2013. Change Biol. 18:1042–1052.

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